1. Field of the Invention
The invention relates to a combination transmission-differential arrangement having power input at a point between two friction type transmissions with the drive ratios at each transmission being adjustable so that minimum wheel or track slippage occurs.
2. Prior Art
There are any number of single ended friction drive transmissions available. However, double ended friction drive transmissions driven by a functionally central drive wheel are not known and the use of such transmissions along with only individual differentials for both of the friction drive transmissions is likewise not known. Thus it is not known to adjust the drive ratios at such transmissions to arrange for minimum slippage at the wheels or tracks of a vehicle. Accordingly a problem of slippage does exist when a vehicle is turning and the transmission transmitting power to each wheel or track thereof is supplying the same torque at the same speed. Declutching of friction drive transmissions is theoretically practical and could be utilized to simply declutch the transmission on one side of a vehicle during turning. This could be done for example by having a valve which activates as the steering wheel of the vehicle is moved a significant amount. However, this could lead to a waste of power and somewhat uneven motion of the vehicle. Hence, declutching alone is not a solution to the above mentioned slipping problem.